0 引言
1 研究区概况
2 样品与实验方法
3 返排液/采出水的地球化学特征
3.1 元素地球化学特征
表1 AY7-4井返排液/采出水地球化学组成Table 1 Geochemical composition of flowback/produced water from Well AY7-4 |
样品 编号 | K /(mg/L) | Na /(mg/L) | Ca /(mg/L) | Mg /(mg/L) | NH4 + /(mg/L) | Cl /(mg/L) | Br /(mg/L) | SO4 2- /(mg/L) | Li /(mg/L) | B /(mg/L) | Sr /(mg/L) | Cu /(μg/L) | Mn /(μg/L) | Mo /(μg/L) | Pb /(μg/L) | δD /‰ | δ18O /‰ | Br/Cl /(mol/mol) | B/Cl /(mol/mol) | Li/Cl /(mol/mol) |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
配水 | 5.0 | 3.5 | 71.0 | 9.4 | 23.3 | 57 | 0.002 | 0.010 | 0.8 | 0.3 | 1.2 | -44.1 | -7.2 | 0.001 4 | 0.000 5 | |||||
滑溜水 | 29 | 1 564 | 109 | 17 | 8 | 2 104 | 15 | 255 | 0.0 | -39.5 | -6.1 | 0.003 1 | ||||||||
F1 | 114 | 6 968 | 246 | 45 | 77 | 10 841 | 48 | 11 | 12.4 | 7.2 | 40.3 | 186 | 463 | 80.2 | 1.7 | -31.6 | -4.3 | 0.002 0 | 0.002 2 | 0.005 8 |
F2 | 56 | 3 636 | 152 | 28 | 42 | 5 354 | 23 | 224 | 7.7 | 6.5 | 23.6 | 199 | 414 | 25.9 | 6.9 | -36.7 | -5.1 | 0.001 9 | 0.004 0 | 0.007 3 |
F3 | 55 | 3 113 | 119 | 44 | 38 | 4 645 | 22 | 179 | 6.2 | 5.2 | 19.8 | 136 | 299 | 27.0 | 0.7 | -38.3 | -5.5 | 0.002 1 | 0.003 7 | 0.006 9 |
F4 | 56 | 3 383 | 121 | 45 | 47 | 4 869 | 21 | 286 | 6.3 | 5.1 | 19.2 | 304 | 708 | 14.5 | 9.1 | -37.5 | -5.4 | 0.001 9 | 0.003 5 | 0.006 6 |
F5 | 68 | 3 537 | 177 | 33 | 43 | 5 268 | 26 | 166 | 6.8 | 5.5 | 19.6 | 145 | 513 | 36.9 | 8.6 | -36.7 | -5.3 | 0.002 2 | 0.003 4 | 0.006 6 |
F6 | 82 | 4 760 | 220 | 35 | 53 | 7 125 | 30 | 263 | 10.2 | 8.0 | 28.1 | 198 | 709 | 42.9 | 2.9 | -35.2 | -4.8 | 0.001 9 | 0.003 7 | 0.007 3 |
F7 | 82 | 4 812 | 222 | 42 | 55 | 7 206 | 30 | 233 | 9.8 | 7.0 | 25.6 | 363 | 640 | 39.9 | 0.2 | -37.3 | -5.1 | 0.001 9 | 0.003 2 | 0.007 0 |
F8 | 115 | 7 168 | 335 | 49 | 70 | 11 057 | 46 | 19 | -33.6 | -4.5 | 0.001 8 | |||||||||
F9 | 64 | 3 350 | 190 | 24 | 38 | 4 951 | 21 | 116 | 7.0 | 6.7 | 17.1 | 262 | 471 | 32.5 | 2.0 | -37.5 | -5.3 | 0.001 9 | 0.004 4 | 0.007 2 |
F10 | 130 | 8 243 | 354 | 56 | 80 | 12 799 | 53 | 14 | 18.3 | 11.0 | 53.2 | 631 | 938 | 58.0 | 1.8 | -34.0 | -4.4 | 0.001 8 | 0.002 8 | 0.007 3 |
F11 | 135 | 8 623 | 368 | 59 | 82 | 13 395 | 59 | 10 | 20.0 | 11.1 | 57.0 | 815 | 1 128 | 11.0 | -32.3 | -4.1 | 0.002 0 | 0.002 7 | 0.007 6 | |
F12 | 151 | 9 413 | 419 | 65 | 90 | 14 755 | 63 | 8.8 | 30.8 | 13.0 | 70.9 | 987 | 1 267 | 22.2 | 7.9 | -31.5 | -3.8 | 0.001 9 | 0.002 9 | 0.010 7 |
F13 | 141 | 8 743 | 334 | 52 | 85 | 13 478 | 57 | 23 | 29.5 | 12.4 | 58.7 | 958 | 959 | 21.0 | 0.9 | -32.6 | -3.8 | 0.001 9 | 0.003 0 | 0.011 2 |
F14 | 127 | 7 825 | 259 | 41 | 76 | 11 913 | 50 | 29 | 25.2 | 12.7 | 47.5 | 902 | 743 | 23.1 | 3.5 | -32.5 | -4.0 | 0.001 9 | 0.003 5 | 0.010 8 |
F15 | 128 | 8 033 | 258 | 43 | 77 | 12 124 | 50 | 19 | 25.5 | 12.8 | 48.2 | 976 | 719 | 22.2 | 0.7 | -31.4 | -3.7 | 0.001 8 | 0.003 5 | 0.010 8 |
F16 | 123 | 8 669 | 306 | 50 | 70 | 13 232 | 56 | 7.1 | 24.3 | 12.4 | 54.0 | 1 004 | 811 | 33.1 | 1.2 | -31.0 | -3.7 | 0.001 9 | 0.003 1 | 0.009 4 |
F17 | 144 | 9 330 | 339 | 57 | 90 | 14 348 | 58 | 1.5 | 12.2 | 10.0 | 25.9 | 660 | 390 | 25.4 | 0.0 | -30.7 | -3.7 | 0.001 8 | 0.002 3 | 0.004 4 |
F18 | 99 | 6 618 | 171 | 28 | 67 | 9 756 | 39 | 37 | 12.6 | 9.5 | 25.1 | 790 | 396 | 24.8 | 5.1 | -31.7 | -4.2 | 0.001 8 | 0.003 2 | 0.006 6 |
F19 | 98 | 6 648 | 171 | 28 | 65 | 9 789 | 38 | 35 | 11.7 | 10.0 | 25.6 | 742 | 392 | 24.9 | 0.0 | -32.9 | -4.4 | 0.001 7 | 0.003 4 | 0.006 1 |
F20 | 109 | 7 247 | 172 | 30 | 72 | 10 686 | 47 | 9.0 | 13.3 | 9.6 | 30.4 | 822 | 383 | 10.7 | 0.0 | -30.6 | -4.0 | 0.001 9 | 0.002 9 | 0.006 3 |
F21 | 120 | 8 024 | 182 | 34 | 79 | 11 943 | 51 | 3.4 | 15.3 | 10.5 | 39.0 | 849 | 402 | 10.3 | 0.5 | -29.4 | -3.7 | 0.001 9 | 0.002 9 | 0.006 5 |
F22 | 129 | 8 634 | 212 | 38 | 85 | 12 906 | 52 | 2.7 | 17.3 | 11.6 | 44.5 | 969 | 440 | 14.0 | 0.0 | -29.3 | -3.7 | 0.001 8 | 0.003 0 | 0.006 8 |
F23 | 140 | 9 376 | 254 | 46 | 92 | 14 163 | 59 | 2.9 | 18.7 | 12.0 | 51.8 | 1 028 | 435 | 15.2 | 2.6 | -29.7 | -3.5 | 0.001 8 | 0.002 8 | 0.006 8 |
F24 | 146 | 9 771 | 277 | 51 | 96 | 14 838 | 59 | 1.6 | 19.1 | 11.6 | 53.5 | 1 068 | 498 | 12.4 | 0.5 | -28.9 | -3.5 | 0.001 8 | 0.002 6 | 0.006 6 |
F25 | 165 | 11 186 | 361 | 68 | 109 | 17 272 | 71 | 23.7 | 12.2 | 75.1 | 1 180 | 634 | 15.2 | 3.9 | -28.7 | -3.4 | 0.001 8 | 0.002 3 | 0.007 0 | |
F26 | 165 | 11 201 | 361 | 68 | 109 | 17 304 | 70 | 2.6 | 22.7 | 12.1 | 75.5 | 1 154 | 637 | 11.8 | 8.1 | -29.0 | -3.4 | 0.001 8 | 0.002 3 | 0.006 7 |
F27 | 183 | 12 350 | 428 | 82 | 122 | 19 223 | 79 | 27.3 | 12.6 | 95.2 | 1 262 | 788 | 9.2 | -28.2 | -3.2 | 0.001 8 | 0.002 2 | 0.007 3 | ||
F28 | 187 | 12 578 | 444 | 85 | 124 | 19 695 | 80 | 28.7 | 12.3 | 96.6 | 1 305 | 774 | 7.9 | -28.9 | -3.3 | 0.001 8 | 0.002 1 | 0.007 5 |
图3 AY7-4井、威远、长宁和涪陵地区页岩气压裂返排液/采出水元素组成箱式图(返排时间在40 d内,威远、长宁、涪陵数据来自文献[1, 8-9])Fig.3 Box plot of elements in flowback/produced water from Well AY7-4, also shown are thoses from Weiyuan, Changning and Fuling shale gas fields(days after hydraulic fracturing are within 40 days, data of Weiyuan, Changning, Fuling are from Refs.[1,8-9]) |
图4 AY7-4井和威远页岩气田返排液/采出水Mg—Cl、Ca—Cl元素组成图,同时出示的还有四川盆地震旦系、寒武系、二叠系、三叠系飞仙关组和须家河组地层水(除AY7-4井,其余数据来自文献[1])Fig.4 Plots of Mg versus Cl and Ca versus Cl of flowback/produced water from Well AY7-4 and Weiyuan shale gas field, also shown are data formation water from Sinian, Cambrian, Permian, Triassic Feixianguan and Xujiahe formations (except Well AY7-4, other data are from Ref. [1]) |
3.2 氢氧同位素地球化学特征
4 返排液/采出水成因与来源
5 返排液/采出水潜在环境污染风险
表2 AY7-4井压裂返排液/采出水化学组成与不同标准的比较Table 2 Comparison of the composition of flowback/produced water from Well AY7-4 to various standards |
水样/标准 | Na /(mg/L) | Cl /(mg/L) | B /(mg/L) | Cu /(mg/L) | Mn /(mg/L) | Mo /(mg/L) | Pb / mg/L) | SO4 2- /(mg/L) | NH4 + /(mg/L) |
---|---|---|---|---|---|---|---|---|---|
AY7-4井返排液平均值 | 7 616 | 11 605 | 10.0 | 0.74 | 0.63 | 0.025 | 0.002 9 | 68 | 76 |
《生活饮用水卫生标准》(GB 5749—2022) | 200 | 250 | 1.0 | 1.0 | 0.10 | 0.07 | 0.01 | 250 | 0.5 |
《农田灌溉水质标准》(GB 5084—2021) | — | 350 | 1~3 | 0.5~1.0 | — | — | 0.2 | — | — |
《污水综合排放标准》(GB 8978—1996) | — | — | — | 0.5 | 2.0 | — | 1.0 | — | 15 |
《地表水环境质量标准》(GB 3838—2002) | — | 250 | — | 0.01~1.0 | 0.1 | — | 0.01~0.1 | 250 | 0.15~2.0 |
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